Rifle-barrel



J. D. PEDERSEN.

RIFLE BARREL,

Patented 0013. 12, 1920.

APPLICATION FILED JULY 1,855,422.

UNITED STATES JOHN D. PEDEBS'EN, 0F JACKSON, WYOMING.

RIFLE-BARREL.

Specification of Letters Patent.

Patented Oct. 12, 1920.

Application filed July 14, 1917, Serial No. 180,492. Renewed March 22,1919. Serial No. 284,516.

T 0 all whom it may concern.

Be it known that JOHN D. PEDERsEN, a citizen of the United States,residin in Jackson, inthe'county of Lincoln and S nate of Wyoining, haveinvented certain new and useful Improvements in Rifle-Barrels, of whichthe following is a specification.

This invention relates to rifle barrels, and a principal object is tofurnish an improved barrel especially adapted'for use in rifled shoulderarms. A further object is to provide means whereby the work of finallyshaping the projectile to conform to and engage with the rifling ribsand in the rifling grooves, will be accomplished in successive stages orperiods, so that said work will be 7 carried out in the rearward portionof the barrel and also in a modulated and progressive manner. p

As regards some features thereof, my present invention, is in the natureof a modification of, and an improvement on therlfle barrel described inmy copending applica-, tion Serial No. 177,252, filed June 27, 1917;some features, however, of the improved rifle barrel herein describedare regarded as being within the description, and as being covered bycertain of the claims of said prior application. 7

i particular purpose of the present invention is to furnish a rifled gunbarrel especially adapted for using un-cased (or thinly cased or coated)projectiles,such as bul lets of lead or those of similar character,-

in a highly effective manner, and therefore to provide for propellingsuch projectiles,

. oibullets, with powder charges of relatively high power; also,.toaccomplish these results in connection with a firearm barrel,-such forinstance as the barrelof a military shoulder-arm -in which the riflingisof a standard'form and construction suitable for using encasedprojectiles of the usual elongated form. Further advantages and objectsare "the following description.

pointed out and explained in the course of In the drawings accompanyingand forma "inga part of this specification, Figurelis a. sideview,principally in section, and barrel made in accordance with mypresent improvements, and of composite construe with some parts brokenaway,of a--rifle 1 tion.-

' Fig. 2 is an end view, as seen from the left-hand in Fig. 1.

Figs; 3 and 4: are cross sections in lines X and K, respectively, ofFig. 1; Figs. 3 and 4 are end views (on an enlarged scale) of aprojectile at successive "stages of the surface formation thereof, aseffected by the successive riflings shown in Figs. 3 and 4,respectively. I

' Fig. 5 is an enlarged detail view especially arranged for illustratingcertain features of the rifling, as hereinafter more fully explained.

F'g. 6 is a view analogous to a portion of Fig. 1, for illustratingcertainvariations in v the form or arrangement of successive portionsof" the rifling.

Similar reference characters designate like parts in all the views. I

Referring to the drawings, B indicates a rifle barrel of ordinarycharacter; it may have, in practice, any desired or suitable externalsize and form. To facilitate illustration, a large portion of the lengthis broken away at 20, in Fig. 1, so that the rearward barrel of theclass common to military shoulder arms; These barrels are now generallymade with the bore thereof,-as E,

Fig. 1,-having a diameter of about three- 1 tenths. of one inch, but inpractice this bore may be smaller or larger, as may be required bythesize and character of the firearm.

The main barrel, B, may be provided with the usual form of helicalrifling, either of uniform twist, or gain twvist, as may be desired';-however, I prefer to use in this barrel the. more. common uniform twist.The number of the rifiing ribs may vary, three to six being withincommon practice, but'I prefer, for general use, to have the barrel Bprovided with four ribs, as 5,- see Figs l, 4, 5 and 6. To aid clearnessof illustration, the usual depth of the rifling grooves, 5",- (Fig. 4),(and, of course, the

height of. the rifling ribs 5), has. been somewhat exaggerated in thepresent drawing. Said depth of grooves and height of ribs are, ofcourse, to be measured in a direction radial to the geometric axis ofthe barreL- At the rearward end thereof, the barrel :B," (,Fig. 1), isshown at ,10, externally reduced in size and threaded, by way of showingone ordinary wa. whereby the barrel may be removabl xed in the usualreceiver, or frame, hot shown) of a firearm,

. in 'a well-known manner. Also, said main barrel B is shown as beingbored out, (to

the lines. 12, 12, Fig. 1), to form the usual cartridge chamber,suitable for the shell, or powder-case]? (not shown) of a high- 1 powercartridge having a long-range prosame size and proportions as thechamber 12,

' jecetile.

the member D will not beremovable.

in my Into said chamber'12, a secondary barrel, D, isshown closelyfitted, thus forming a complete barrel having a composite construction.It should be understood, howu ever, that in some instances, if desired,said portion orauxiliarybarrel, D, may be made integral with the mainbarrel, B; in this case, of course, the barrel B will have no chamber 12available for separate use, since an integral form of the completebarrelis not shown herein, but has been illustrated aforesaid applicationSerial No. 177,252.

In the composite form of the barrel shown in Figs. 1, 2, 3 and 6, themember D is ex-. tended rearwardly of the member B, (Figs. 1, 2), and isthere shown enlarged, as at 14, and provided with a cartridge chamber15;

this chamber should be of suitable size and proportions for receivingthe cartridges which, in any given instance, are to be used 1n thecomposite barrel. 'Said chamber 15, 111801116 instances if desired, maybe of the relatively small rifling ribs for initially grooving aprojectile, and which forward of said small ribs, (and forward ofsaid'zone N '1 of the intial projectile gro oving action), is

provided with rifling rribs arranged for changing the initial groovingofthe projec, tile. A further feature is that said zone ,N

of initial grooving, is extended forwardly from said chamber 15 to alength or bint forwardo'f the'position when the gases nor:

Such

mally will have reached their maximum pressure, so that the projectilewill pass from the relatively small to the larger rifling ribs at a timewhen the as-pressure is beginning to decrease; durlng this period,- ortime-interval,-i't is believed that the velocity of the projectile willbemost rapidly increasing. This increase, however, of velocity issupposed to disappear at or somethereof of a diameter larger than thediame-'.

ter of the bore of the main barrel, and is' also shown provided withrifling ribs, as 7 swith intervening grooves 7 ;-which are not onlysmaller and more numerous than the ribs 5 of the main barrel, but arealso located farther from the geometric axis of the barrel. In practice,the number of the ribs-7 relative to the number of the ribs 5, may bevaried, but I prefer to make said smaller ribs about double the numberof the larger ribs; such an arrangement is shown-in Fig. 5, where thefour large ribs 5. are shown used in combination with eight of thesmaller ribs 7. This arrangement and construction I have found bypractical tests to be particularly effective in operation. 1

In Fig. 5 a further feature is illustrated,

' in that the outer circle, at 31,-ofthe ribs 5 and grooves 5", of themain rifling, is also substantially coincident with the inner circle ofthe ribs 7 and grooves 7 of the 'auxlli'ary rifling. Thus it may be saidthat the two series of ribs and grooves,-as seen in an endview of thebarrel,occupy two concentric annular zones, respectively, the r1bs 7being in the outer zone indicated by the circles at 31 and 32, and theribs 5 being in the inner annular zoneindicated by the circles at 30 and31, Fig. 5. A pair of the small ribs 7 are also shown in Fig. 5 locatedin a symmetrical position circumferentially with relation to each one ofthe larger ribs 5, but

in-"practice, this-symmetry of arrangement,

while regarded as preferable, may be omitted in some instances. In thisview, Fig. 5, of

course 'thecervature, or spirality, of the ribs is disregarded.

In Fig. 1, the ribs 7 are indicated as extending forward close to therearward ends of the larger ribs 5,'but it should be under"- stood thatin some instances if desired, a

space, or un-ribbed zone, as 8', Fig. 6, may

for the complete barrel. By its motion and e great momentum acquired intraversing the zone N, the projectile will readily pass from the ribs 7and over said zone 8 andcontinue '1 30 ing with the rifling 5. Thus thesmall projecting ribs (F ig. 3 raised on the projectile by the small riing-ribs 7 may be reduced,

' or ironed out by the cylindrical surface of the bore within the zone8'.

In the zone z,Figs. 1, 6,the ribs 5 are shown tapered or reduced to awedge-like form, thus providing for a gradual engagement of theprojectile with said ribs, and

avoiding so sudden a shock or resistance as otherwise might occur; thistapering form of the rib-ends of the rifling 5 may, how

- ever, be omitted in some instances, whenever stage of'the combustionof the powder. Consequently, during that initial forward move-'spondingly increase thegas-space beforejthe desired, and is notessential to the principal features of my present invention.

The relativeeifects of the successive rifling ribs, Tand 5, upon aprojectile are approximately shown in Figs. 3? andi l which correspondwith the inner outlines of the bore of the barrel, in Figs. 3 and 4,respectively. Thus Fig. 3 shows a cross-section of a projectile, J, asinitially by the ribs 7 Fig. 3, to form the initial ribs 7 on theprojectile. Similarly, Fig. 4: shows said projectile as having formedtherein the new and larger grooves, 5 corresponding to the ribs, 5, ofthe barrel B,

i in Fig. 4; in this latter operation, the initially-formed ribs on theprojectile,Fig. 3*,are reduced and eliminated by a-complete re-formingof the outer surface-portion of the projectile.

The slight resistance offered by the relatively small ribs 7 to theinitial forward movement of the rojectile, permits this movement,-,onthe ringof a cartridge,- to begin at a time (at a moment) when thegas-pressure is-still comparatively ,low, so that the space behind theprojectile will be materially enlarged during a very early ment, theprojectile will havenot only a-low velocity, but also, for the instant,a low degree of: acceleration, so that a minimum amount of power will-beconsumed durin that moment in inaugurating the rotation-o the.projectile, and thereby permit'a -more rapid acceleration of the forwardmovement under agiven and relatively low gas pressure. Thus the rapidlyincreasing forward movement while the projectile is'subjected to the lowrib-resistance, -tends to corregas-pressure' can rise to its maximum. Asa result of this action, the curve by which the ga's-pressure is usuallyrepresented in a wellknown diagrammatic manner, Wlll be materiallymodified in a way to'show a delay,-- as compared with the hithertoaccepted prac- .tice, vof the moment when the gas will attain maximumpressure; this normally operates to reduce the maximum strain upon thebarrel due to the burning therein of a given quantity'of powder behind aprojectile of a given weight, and also,w ithin a given limit of thatstrain,provides for burning a relatively larger quantity ofpowder behinda projectile of a given weight. 1

By reason of'the, modulation, as above explained, of the forces andpressures, the torsional strain on the initial rifling (and especiallyduring the first one or two inches of said forward movement of theprojectile), is believed to be materially less than normally occurringwith the usual style of rifling which has ribs-of uniform cross-sectiondimensions throughout the length of the barrel. Hence my presentimprovements are especially applicable to rifled firearms hav- .85 ingbarrels of composite construction, and in which a main barrel is adaptedfor using high-power cartridges and is also, for some uses, providedwith an adapter, the bore of which forms a rearward extension oftl1e-.90 bore of the main barrel; one arm of this class,a militaryshoulder-arm,is described in m application filed April 28th, 1917,Serial 0. 165,171, towhich reference may be had. In practice, by thetime'when the projectile has reached the forward end of the initial ribs7 and thus come to the larger rifling ribs 5, the projectile hasacquired such a I velocity and momentum that it will take the riding. ofthe main barrel without difliculty. As a result, therefore, of,the saidfeatures and mode of action, when the barrel is provided with therelatively thin adapter extension or supplemental barrel, as hereinshown, this is so far protected and relieved of the otherwise heavystraix'nas to be reliable and effective under the severe conditions ofcontinued service. ,Thus, also, I avoid the highly destructive actionupon the pro- 11. jectile, which occurs when the bore of theadapter-barrel is a smooth-bore (not herein shown); that construction,asI have found by extended trials; allows the projectile to initiallyadvance toov rapidly, so that on striking the rifling ribs of the mainbarrel,-

and being then without rotation,-the projectile will often be so cut'anddeformed as j greater than that of the well-known risingpressure zone ofa pressure-diagram for the cartridges proper for use in the barrel B,so" that,as herein 'explained,the increased resistance due to theprojectile encountering the larger ribs 5, will be delayed, and so willnotoccur until after the gas-pressure has begun to reduce. Theminimumdength of the zone N may be regarded as equal to about two andone-half times the diameter of the bore E, while a normal and preferablerange thereof may be between four and ten diameters or calibers,according to size of bore, the twist of the rifling, and the characterand power of the cartridges to be used; all these matters or factors arereadily ascertainable by trial in any particular instance.

'The breaking of the surface of the bullet into small undulations by theaction of the rifling ribs 7, serves to prepare the bullet for thesecond and larger change of form which is effected by the main rifling5. Thus a it may be said that the rotation of the bullet is effectedfirst by means of a temporary, and preliminary formation thereof, and isthen continued by means of-a second and different formation thereof. Therotation is inaugurated'by the auxiliary rifling 7, acting upon thesmall ribs, as 7", of the bullet Y J,-as indicated in Fig. 3 ,and therotation is accelerated and continued by the main rifling, 5, actingupon the larger ribs, 7, (Fig. 4'), which are formed on the bullet aftersaid preliminary formation thereof has been obliterated. Thus theinitial grooving of. the projectile is normally followed by there-grooving thereof, and this is accompanied by a reduction of theoutside diameter,and sometimes by a slight elongation,as now will bereadily understood by a comparison of the several circles at 30, 31 and32,- and of Figs. 3 to 5, inclusive. In some instances, if desired,especially in firearm barrels of larger bore,the inner circle of theinitial grooving may be slightly smaller than the outer circle of thefinal grooving of the bullet; however, I deem it to be desirable that inthe initial grooving operation, the ribs 7 shall not cut so deeply intothe bullet but that the final grooving operation will fully smoothout,or seal, the initially-formed ribs and grooves of the bullet. When theseoperations are properly carried out, the

, symmetrical arrangement of the ribs 7 and 5,-as already described inconnection with Fig. 5,-becomes relatively unimportant, so that themember D may in practice be turned to have any desired position relativeto and within themember B.

Having thus described myinvention, 1

claim 1. A rifle barrel having in the rear end thereof a cartridgechamber, and having a bore which in a zone thereof adjoining saidchamber is provided with 'a series of rifling ribs arranged forinitially grooving a projectile with one number of grooves, and

which forward of said initially-grooving ribs is provided with anotherseries of rifling ribs that are in position and adapted r51" firstobliterating the initial grooving and for then re -grooving theprojectile with a different grooving.

'ferent series of grooves,

which forward of said initially-grooving ribs is provided with riflingribs of a number less than the number of said initial rifling ribs, andthat are in position and adapted for first obliterating the initialgrooving and for then re-grooving the projectile with a differentgrooving.

3. A rifle barrel having a cartridge cham ber and having forwardly fromsaid cham-- ber a bore which in a zone thereof adjacent to said chamberis provided with a relatively numerous series of rifling ribs forinitially forming on the projectile a numerous series of relativelysmall ribs and grooves, and which forward of said zone is provided witha different and less numerous series of rifling ribs arranged forforming on the projectile a different and less numerous series ofrelatively larger ribs and grooves.

l. A rifle barrel having a cartridge chainber, and having forwardly fromsaid chamber a bore which in a zone thereof adjoining said chamber isprovided with a series of rifling ribs for initially grooving a projectile with one number of grooves, and which forward of said zone isprovided with rifling ribs that are in position and arranged forre-grooving the projectile with a different number of different grooves,the rifling ribs in said zone having the inner circle thereof of adiameter larger than the diameter of thg, inner circle of saidre-grooving riflin r1 s.

5. A rifle barrel having a cartridge chamber, and having forwardly fromsaid cham ber a bore which in a zone thereof adjoining said chamber isprovided with a series of relatively small rifling ribs for initiallygrooving a projectile, and which forward of said zone is provided with aseries of larger rifling ribs that are in position and arranged forre-grooving the projectile with a difsaid series of smalle'rrifling ribshaving the inner circle thereof of a diameter larger than the diameterof the inner circle of said series of larger rifling'ribs.

6. Arifle barrel having a cartridge chamber, and having a bore. which ina zone thereof adjoining said chamber is-provided with relatively smalland numerous rifling ribs arranged for initially grooving a projectile,and which forward of said small ribs is provided-with larger and lessnumerous rifling ribs that are in position and adapted for obliteratingsaid initial grooving and for then re-grooving' the projectile. i I

berfand having a bore which in a zone thereof adjoining said, chamber isprovided with a series of relatively small and numerous rifling ribsarranged for initially grooving a projectile, and which forward of saidsmall-ribs is, provided with a series of larger and less numerousrifiing ribs that are in position and adapted for obliterating saidinitial grooving and for -then re-grooving the projectile, said seriesof the smaller rifling ribs having'the inner circle, thereof of adiameter: larger -than the diameter of the inner circle of said seriesof the larger rifling ribs.

8. A rifle barrel ofeomposite construction and having a continuous bore,and comprising a main barrel having at the rear end thereof a shortsecondary barrel provided with a cartridge chamber, and adjacent to saidchamber provided with a series of relatively small rifling ribs forinitially grooving a projectile with one number of grooves,

said main barrel at a distance forward ofsaid small ribs being providedwith a different series of relatively larger rifling ribs that are inposition and adapted to regroove the projectile with a differentgrooving.

9. The hereindescribed improvement in composite rifle barrels, itcomprising a main barrel having in the bore thereof a series of riflingribs, and having a cartridge chamber in the rearward end thereof, incombination with a secondary barrel having the forward end thereofremovably. inclosed insaid cartridge chamber of the main bar: rel, andhaving in the rearward end there of and rearward of the main barrel acar tridge chamber and in the bore thereof having a series of riflingribs for initially grooving a projectile with one number of grooves,said main barrel having the bore thereof of a diameter smaller than thediameter of the bore of the secondary barrel.

JOHN D. PEDERSEN.

Witnesses:

L. E.-WETMORE, E. C. GILBERT.

